1. Field of the Invention
The present invention is directed to an actuation force generating arrangement for a centrifugal clutch including a housing arrangement, a supporting element which is movable axially with respect to the housing arrangement, and a plurality of centrifugal members. Every centrifugal member is supported with respect to the housing arrangement in a first supporting area extending radially from the inside to the outside and is supported with respect to the supporting element in a second supporting area extending radially from the inside to the outside, and every centrifugal member is displaceable radially under the influence of centrifugal force along a pair of supporting areas which comprises a first supporting area and a second supporting area.
2. Description of the Related Art
A centrifugal clutch for use in motor vehicles is known from DE 32 20 572 A1. The roller elements acting as centrifugal members comprise a central roller with a larger diameter which can roll on a supporting area formed at the housing arrangement. Two rollers having a smaller diameter which are fixedly connected to one another and rotatable with respect to the central roller are provided at both sides of this central roller and can roll radially at a supporting area or at two supporting area portions separated in circumferential direction. The supporting areas formed at the housing on the one side and at the pressing plate on the other side are inclined relative to one another so that they move toward one another radially from the inside to the outside. As the result of a displacement of the centrifugal members toward the radial outside caused by centrifugal force, the centrifugal members being supported at the housing arrangement impinge axially on the pressing plate and accordingly move it in the engagement direction. When the centrifugal force reaches a sufficiently high value by means of increasing rotational speed, the centrifugal members reach a radial outer end position in which they strike against and come to rest at an outer circumferential wall of the housing arrangement. This contacting of the centrifugal members and housing arrangement generally produces a noticeable impact noise and, moreover, stresses the centrifugal members as well as the housing arrangement. This effect of the impacting of the centrifugal members is increased when, as is proposed in WO 02/48530 A1, the supporting areas forming a pair extend in their radial outer area at a smaller relative inclination angle, that is, for example, extend virtually parallel to one another, in order to be able to provide a hysteresis effect in the shifting characteristic of a centrifugal clutch of this type. Upon entering this area of the smaller relative inclination angle of the associated supporting areas, the counterforce which acts against an outward radial movement of the centrifugal members decreases spontaneously, so that the centrifugal members strike against a stop, e.g., at the housing arrangement, virtually without deceleration.